1. Field of the Invention
This invention relates to a drafting means for a textile machine, especially for a spinning frame. More specifically, it relates to a weighting device for top rollers of a drafting means, in which a fiber bundle is drafted between two successive pairs of top and bottom rollers.
2. Description of the Prior Art
There are two types of roller weighting device in conventional systems; a dead weight type and a spring loaded type. The former is inconvenient in handling and lacks a damping effect against vibration. The latter is better on the abovesaid points, however, cannot easily maintain a uniform weighting force on all of the rollers arranged throughout the frame. Since dimensional differences between rollers cannot be avoided due to inherent manufacturing error or abrasion during usage, the spring force on the rollers varies unless the displacement of the spring is adjusted individually.
In addition, these two conventional devices have the common drawback of a troublesome adjustment. That is, to change the load on the rollers, e.g., when changing the draft ratio, adjustment or replacement of the weights or springs for the rollers is necessary.
In fasciated yarn spinning, in which yarn can be produced at a high rate 10 times faster than by ring spinning, the accuracy and uniformity of the roller weighting is particularly important, having a much more serious effect on the quality of the resultant yarn and yarn breakages during spinning than in the case of conventional ring spinning.